Asbestos was once seen as an everyday part of life. Now scientists know that it causes one of the most vicious forms of lung cancer. Health Correspondent Barry Nelson investigates the mesothelioma timebomb that awaits the region.

MESOTHELIOMA is a long word, and one which strikes fear into the heart of anyone who worked in shipyards and construction sites of Britain before the 1980s.

Until the 1970s, the dangers of working with asbestos were not fully understood. But as more research pointed to the inhalation of tiny asbestos fibres as the cause of this fatal form of lung cancer, the alarm bells began ringing.

Tough legislation introduced to ban the use of asbestos meant that the risk to workers of contracting mesothelioma was dramatically reduced from the late 1970s onwards. But imports of asbestos - particularly important as a heat retardant in the construction of ships - were at their peak in the 1970s.

Because of the long time lag before mesothelioma develops, there is an interval of between 30 and 40 years before acute symptoms of pain and breathlessness develop, a time delay which means that chest physicians in the North-East, once one of the major shipbuilding centres in Britain, are bracing themselves for a wave of mesothelioma patients.

Experts now predict that a "silent epidemic" of mesothelioma will peak in the next 10 to 15 years, and nationally, chest physicians are expecting around 80,000 people to die from this terrible, untreatable condition, which claims around 1,700 lives a year in the UK.

Dr Chris Stenton, a chest physician at Newcastle's Royal Victoria Infirmary, talked about the challenge posed by this disease at a conference held on Tyneside recently.

Dr Stenton currently sees 200-300 patients with mesothelioma at his clinic in Newcastle every year, a figure he expects to increase over the next decade. "We are about one third of the way through the epidemic, so most deaths are still to come," he says.

Disconcertingly, Dr Stenton points out that by stepping out into the streets of our cities, we are almost certainly breathing in microscopic asbestos fibres.

"Everybody has been exposed to asbestos. There are fibres in the air. If you step out into the centre of Newcastle and take a deep breath you will almost certainly breath in one fibre per lungful. It comes from old buildings. It is there in the air."

Thankfully, there is no need to panic or stay indoors. Dr Stenton says that mesothelioma only seems to be triggered by massive exposure to asbestos fibres.

"Most of the people I see have been exposed to very high levels, many millions of fibres. You are up to 10,000 times more likely to get this disease if you have been exposed to asbestos, but it is very uncommon for people with low exposure to get tumours," he says.

But while this means that shipyard workers, construction workers and those who worked in the asbestos industry during the unregulated years are most at risk, there are examples of patients who became ill because of indirect exposure.

In a number of cases, women who washed their partner's workclothes developed the disease while in at least one other case a particularly houseproud woman who insisted on cleaning her windows when an asbestos shed was being demolished next door became ill with mesothelioma, according to a local GP.

The tumour spreads "like a drop of oil on water", according to Dr Stenton, around the external lining of the lung, squeezing the organ and producing severe pain, breathlessness and - eventually - death. But what actually causes the tumours?

To begin to answer the question, Dr Stenton says we need to understand more about the cause of the problem.

"Asbestos is a mineral, which is dug out of the ground. It has a long, thin fibrous structure which can be spun into cloth and compressed into bricks," he says.

Widely used as an insulating material - from lagging pipes in ships, factories, hospitals and offices, to an integral part of ironing boards - it is still present in many of our older buildings.

The conventional wisdom is that asbestos is relatively safe if it is left intact, but any disturbance which could generate fibres is strictly controlled by health and safety legislation. That's why specialist firms are the only ones licensed to deal with the stripping out of old asbestos.

Under the microscope, the asbestos fibres form needle-like structures.

Because they are so small they get into the tissue of the lung quite easily and once they are lodged in the tissue some work their way out to the outer edge of the lung.

Dr Stenton says the mechanism which causes mesothelioma is not fully understood but the suspicion is that the needle-like structure damages the DNA of a cell in the exterior lining of the lungs, allowing it to reproduce uncontrollably. "The fibres puncture the cells and then we think it goes on to damage the DNA and causes the cancer."

Apart from spreading around the exterior of the lung and damaging one of the body's most vital organs, it can also spread into other tissue, in some cases forming unsightly bulges on the trunk of the body.

While the disease tends not to affect people until they get into their early 70s, some others are unlucky.

Mick Knighton, from Wallsend on Tyneside, was only 60 when he died from mesothelioma in March 2001. Mick served in the Royal Navy as a young man when asbestos were widely used.

His widow, Christine Knighton, 57, was so traumatised by her husband's illness and rapid decline that she set up a research fund to raise £100,000 try to find ways of treating this terrible disease.

"Mick was a gunner in the navy and he handled asbestos every day. He even had a helmet and gauntlets made from the stuff," says Mrs Knighton, who says the more we can promote awareness of the condition, the more hope there is of funding research. "Mick was given six months to live, he got no treatment or help. There is a desperate need for research," she says.

"We don't really have good treatments," admits Dr Stenton. "We can try radiotherapy or chemotherapy but there is no cure. Treatments are depressingly unsuccessful and are mostly palliative."

While specialists can treat some of the symptoms, such as breathlessness and pain, they are currently powerless to prevent the disease progressing, usually killing the patient within 12 to 18 months after diagnosis.

Radical surgery has been tried in some centres but this has major side-effects and seems only to have extended lives by a few months. Recently, patients at Dr Stenton's clinic have benefited from new chemotherapy drugs but it is still a matter of extending life, rather than a cure.

Dr Stenton is hopeful that a breakthrough might come at some stage in the future. "Immunotherapy, where the body's immune response is stimulated in order to try to destroy the tumour, has had some success," he says. "Another line of attack is gene therapy - infecting the cancerous cells with a virus and then using drugs to kill off the virus, which will hopefully taking the cancer cells with it."

Despite the deep gloom, Dr Stenton points out that some individuals do seem to be able to survive longer than others with the condition.

"My oldest surviving patient has had treatment for six years and she is doing quite well," he says. "We never give up hope."

To contact the Mick Knighton Mesothelioma Research Fund telephone 0191 263 7386 or visit the website http://mickknightonmesorf.mysite.freeserve.com